title: The effect of pyrazines on the metabolism of tryptophan and nicotinamide adenine dinucleotide in the rat. Evidence of the formation of a potent inhibitor of aminocarboxy-muconate-semialdehyde decarboxylase from pyrazinamide.
abstract: The intraperitoneal or oral administration of pyrazinamide and pyrazinoic acid (pyrazine 2-carboxylic acid) resulted in a marked increase of the NAD content in rat liver. The injections of pyrazine and pyrazine 2,3-dicarboxylic acid exhibited no significant effect on the hepatic NAD content. The boiled extract obtained from liver and kidney of rat injected with either pyrazinamide or pyrazinoic acid exhibited a potent inhibitory effect on the aminocarboxymuconate-semialdehyde decarboxylase (EC 4.1.1.45) activity in either lier or kidney, although pyrazinamide or pyrazinoic acid per se did not inhibit the enzyme activity. The unknown inhibitor of aminocarboxymuconate-semialdehyde decarboxylase was dialysable and heat-stable, and mostly excreted in urine by 6 and 12 h after injected of pyrazinoic acid and pyrazinamide, respectively. Pyrazine 2,3-dicarboxylic acid, pyrazine, nicotinamide, nicotinic acid, tryptophan, anthranilic acid, 5-hydroxyanthranilic acid and quinolinic acid exhibited no significant effect on the aminocarboxymuconate-semialdehyde decarboxylase activity in liver and kidney at the concentration of 1 mM in the reaction mixture. The expired 14CO2 from L-[benzen ring-U-14C]tryptophan was markedly decreased by the pyrazinamide injection, while the urinary excretion of 14C-labeled metabolites from L-tryptophan, mainly quinolinic acid, was markedly increased. These results suggest that the glutarate pathway of L-tryptophan was strongly inhibited by the inhibitor produced after the administration of pyrazinoic acid and pyrazinamide. Pyrazinamide but not pyrazinoic acid also exhibited a significant inhibition of the nuclear enzyme poly(ADP-ribose) synthetase in rat liver.
mesh_terms: D000818:Animals; D002262:Carboxy-Lyases / Q000037:antagonists & inhibitors*; D007668:Kidney / Q000201:enzymology; D008099:Liver / Q000201:enzymology; D008297:Male; D009243:NAD / Q000378:metabolism*; D009539:Nicotinic Acids / Q000172:deficiency; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D011718:Pyrazinamide / Q000494:pharmacology*; D011719:Pyrazines / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D014364:Tryptophan / Q000172:deficiency / Q000378:metabolism*
chemical_list: D009539:Nicotinic Acids; D011719:Pyrazines; D009243:NAD; D011718:Pyrazinamide; D014364:Tryptophan; D011065:Poly(ADP-ribose) Polymerases; D002262:Carboxy-Lyases; C024396:aminocarboxymuconate-semialdehyde decarboxylase